Development of a Flood Ensemble Forecast System in Taiwan

Dr. LIEN Ho-cheng 連和政 (NCHC, Taiwan)

Abstract
A real-time forecast system FEWS-Taiwan for both precipitation and water stage are developed in Taiwan. Forecasts with 3-6 hours lead-time are delivered on the hourly basis for 23 river systems of the entire Island during storm events. Observed and forecasted rainfall data from multiple sources are hierarchically combined including those from raingauges, radar, and meso-scale weather models. Through temporal and spatial registrations, the averaged rainfall in each sub-catchment is obtained for runoff prediction. By integrating rainfall-runoff models of each sub-catchment and channel flow models, river simulations are configured in an operational fashion for the entire Taiwan. As different emergency responses are activated on the basis of forecast results which are inherently subject to uncertainty an ensemble concept is proposed in the flood forecast system to indicate the range of predicted quantities. Knowledge about forecast uncertainty provides decision makers with more comprehensive information for making prudent course of actions.

About the Speaker

Dr LIEN obtained his PhD in NCTU (Taiwan) in 1999 and joined the NCHC in the same year. He is currently the Head of the Water Resources Computing Section in NCHC and mainly in charge of water resource computation.

Dr LIEN's main research areas are Hydraulic Computation, Sediment Transport, Hydroinformatics. He has issued numerous papers relating to flow modelling, simulation of dam-break flows, risk analysis for forecasting peak discharge and real time correction of water stage forecast.